Tunable diode laser absorption spectroscopy (TDLAS) based optical fiber methane sensing technology has a
number of advantages compared with conventional electronic methane sensor device, such as high Precision, passive and
intrinsically safe in explosive and hazardous environment as well as immune to electro-magnetic interference. In order to
accurately measure the oxidation rate of coal mine ventilation air methane oxidizer system, and Meet requirements for
accurate measurements to the oxidizer exhaust emissions, A Fiber optic methane monitor based on Distributed feedback
tunable diode (DFB) laser of 1.65um central wavelength is demonstrated. We use a reflective chamber of only a 10cm
effective optical path as sensing gas cell. By the data processing of fitting baseline method, we remove the effect of the
baseline tilt of background Spectral. The system achieves 0 to 0.1% measure range and 5.8*10E-6 minimum detection
sensitivity, and meets the requirements of high accuracy, real-time measure to the oxidizer exhaust emissions.